JPH06256602A - Polypropylene composition - Google Patents

Abstract

PURPOSE:To obtain a polypropylene compsn. improved in releasability, transparency and odor. CONSTITUTION:This polypropylene compsn. comprises (a) 100 pts.wt. propylene- ethylene random copolymer having an ethylene unit content of 1.0 to 6.0wt.% and a melt flow rate (230 deg.C, load: 2.16kg) of 0.2 to 100g/10min, (b) 0.10-0.8 pts.wt. transparent nucleating agent, and (c) 0.01-3.0 pts.wt. silicone oil having a refractive index of 1.42 to 1.54.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION This invention relates to polypropylene compositions, and more particularly to polypropylene compositions having improved releasability, transparency and odor.

[0002]

2. Description of the Related Art In recent years,
Molded products made of polyolefin such as polypropylene
Widely used in medical equipment, stationery, sundries, food packaging, etc. In particular, when used as a medical device, food packaging material, etc., in addition to sterilization by boiling or gas, sterilization is performed by irradiation with radiation such as γ-rays and electron beams.

However, due to the molecular structure of polyolefin, the molecular chain is easily broken by radiation, and when it is exposed to radiation of about 2.5 megarads, which is usually used as a guideline for sterilization dose, decomposition and deterioration of the polyolefin proceed remarkably and impact resistance, etc. The mechanical properties of the syrup and the elution component of low molecular weight increase. There is also a problem that various stabilizers, modifiers, etc., which are generally added for the purpose of preventing oxidation, are deteriorated and remarkably discolored.

Various polyolefin compositions as described below have been proposed in an attempt to solve the problems caused by such irradiation of radiation.

JP-A-60-55005 discloses a radiation-resistant polypropylene composition comprising an ethylene-propylene random copolymer resin having a random ethylene content of 2.8 to 7.0% by weight.

JP-A-60-99147 describes polypropylene resin.
0.01 to 4 parts by weight of sorbitol derivative, tris (2,4-di-t-butylphenyl) phosphite per 100 parts by weight
0.01 to 4 parts by weight, dimethyl succinate 2- (4-hydroxy-2,2,6,6-tetramethyl-1-piperidyl) ethanol condensate 0.01 to 4 parts by weight for irradiation, Disclosed is a polypropylene resin composition having good stability and excellent transparency.

JP-A-60-168740 discloses (a) an ethylene-propylene random copolymer having a polypropylene or ethylene content of 2% by weight or less, and (b) an ethylene-propylene random copolymer having an ethylene content of 4% by weight or more. 0.01 to 0.5 to the ethylene-propylene random copolymer mixture having an ethylene content of 2 to 4% by weight obtained by blending
Wt% diallyl (iso) phthalate or triallyl
Disclosed is a radiation resistant polypropylene resin composition containing (iso) cyanurate.

JP-A-60-215047 discloses a melt flow rate of 0.05 to 10 g / 10 min to 10 in the presence of a radical generator.
Propylene block copolymer weight consisting of 5 to 95% by weight of a propylene homopolymer block denatured to 100 g / 10 minutes and 95 to 5% by weight of a propylene / ethylene random copolymer block having an ethylene content of 2 to 15% by weight. Disclosed is a polypropylene composition comprising 100 parts by weight of the combined product and 0.05 to 0.5 parts by weight of a sorbitol compound.

JP-A-60-215048 discloses a propylene homopolymer block of 5-95 parts by weight and an ethylene content of 2-15.
Propylene-based block copolymer consisting of 95 to 5 parts by weight of propylene / ethylene random copolymer block
Disclosed is a polypropylene resin composition comprising 100 parts by weight and 0.05 to 0.5 parts by weight of a sorbitol compound.

Japanese Unexamined Patent Publication (Kokai) No. 61-73711 discloses that 100 parts by weight of polypropylene or an ethylene-propylene random copolymer is added to 0.005 to 0.2 parts by weight of organic peroxide and triallyl (iso).
Cyanurate or diallyl (iso) phthalate 0.01-0.
Disclosed is a radiation resistant polypropylene resin composition containing 5 parts by weight.

JP-A-61-159437 discloses that (a) propylene homopolymer or ethylene content is at most 3.0% by weight.
Ethylene-propylene random copolymer which is, (b) an ethylene-propylene random copolymer having an ethylene content of 4.0 to 15.0% by weight, and (c) a mixture of organic peroxides, which are independent of each other. The ethylene content in the total amount of the polymer and the copolymer is 1.5 to 4.5% by weight, and the total amount of the homopolymer and the copolymer is 100% by weight.
The mixing ratio of the organic peroxide to 0.001 to 0.25 parts by weight is disclosed, and the propylene polymer composition having a melt flow index of 15 g / 10 min or more is disclosed.

JP-A-3-281647 discloses (a) (i) a propylene homopolymer having a melt flow rate of 0.5 to 15 g / 10 min or a propylene-ethylene random copolymer having an ethylene content of 1% by weight or less. , (Ii) Melt flow rate is 0.
Ethylene content of 2.5 to 5.0 wt% at 5 to 15 g / 10 minutes
A resin mixture with a propylene-ethylene random copolymer of (b), and (b) a sorbitol-based compound of 0.15 to 0.35 parts by weight per 100 parts by weight of the resin mixture as a clarifying agent, and the resin mixture. The ethylene content in 2.
Disclosed is a radiation resistant polypropylene composition, characterized in that it is 3 to 3.5% by weight and the melt flow rate of the composition adjusted by degradation is 25 to 100 g / 10 min.

Further, Japanese Patent Publication No. 2-7968 is a hydrocarbon oil,
Halogenated hydrocarbon oil, phthalate oil, vegetable oil,
An amorphous liquid plasticizer that increases the free volume of the polymer selected from the group consisting of low molecular weight amorphous polymer greases such as silicone oils and hydrocarbon polymer greases, low molecular weight polyester greases and polyaryl ether greases; and Discloses a composition having improved radiation sterilization stability upon irradiation consisting of a semi-crystalline polyolefin mixed with a sterically hindered amine having a specific structure.

However, Japanese Patent Laid-Open Nos. 60-55005 and 60
-99147, JP-A-60-168740, JP-A-61-159437 and JP-A-61-73711, the radiation-resistant polypropylene compositions have insufficient transparency and releasability. There is a problem in that the effect of suppressing the subsequent deterioration of the tensile modulus of elasticity and impact resistance is not sufficient.

JP-A-60-215047 and JP-A-60-215048
Since the polypropylene composition of No. 6 uses a block copolymer of propylene homopolymer and propylene / ethylene random copolymer, it does not have sufficient transparency for use in medical devices such as syringes. There is. Further, there is a problem that the above composition also does not have a sufficient releasing property.

Further, there is a problem that the polyolefin composition of Japanese Patent Publication No. 2-7968 does not have sufficient transparency and releasability.

Further, the radiation-resistant polypropylene composition of JP-A-3-281647 is excellent in transparency and high-speed moldability, and the decrease in impact resistance after γ-ray irradiation is suppressed, but it is not always sufficient. There is a problem that it does not have releasability.

Therefore, for the purpose of improving the releasability of various compositions as described above, addition of unsaturated or saturated fatty acid amides such as oleic acid amide and stearic acid amide has been carried out. However, there is a problem that transparency is deteriorated and odor is deteriorated. Further, since the fatty acid amide bleeds out, there is a problem that the surface of the molded product becomes sticky or the printability is deteriorated. This means that, for example, when the composition is a deep tubular molded article for stationery, medical use, etc., silicone oil may be applied to the inner surface of the tubular molded article in order to improve the slidability of the inner surface. However, there is a problem that the silicone oil is repelled by the bleed-out and adheres in the form of polka dots or mist, resulting in poor transparency and appearance.

Further, for the purpose of improving the releasability of the composition, measures such as blending the composition with silicone oil and sufficiently removing the die taper can be considered, but they are generally used. When silicone oil such as dimethylpolysiloxane is blended, the transparency is significantly lowered by blending the silicone oil, so that the addition amount is limited and it is difficult to obtain sufficient releasability. . In addition, if the punching taper of the mold is sufficiently taken, there is a problem that the product shape is restricted.

Accordingly, it is an object of the present invention to provide a polypropylene composition with improved releasability, transparency and odor.

[0021]

As a result of earnest research in view of the above object, the present inventors have found that a propylene-ethylene random copolymer is provided with a transparent nucleating agent and a silicone oil having a refractive index within a specific range. When blended, the resulting composition is
If the transparency of the propylene-ethylene random copolymer is not impaired, and if it is a tubular product,
The inventors have found that the wettability is good even when silicone oil is applied, and that sufficient mold releasability is exhibited, and the present invention was conceived.

That is, the polypropylene composition of the present invention comprises (a) an ethylene content of 1.0 to 6.0% by weight and an ethylene content of 0.2 to
Propylene-ethylene random copolymer having a melt flow rate of 100 g / 10 min (230 ° C, 2.16 kg load) 10
0 parts by weight, (b) transparent nucleating agent 0.10 to 0.8 parts by weight, (c) 1.
Silicone oil 0.01-3.0 with a refractive index of 42-1.54
And parts by weight.

The present invention is described in detail below. [1] Composition Component (a) Propylene-Ethylene Random Copolymer The propylene-ethylene random copolymer used in the present invention has an ethylene content of 1.0 to 6.0% by weight and a content of 0.1.
Melt flow rate of 2 to 100 g / 10 minutes (230 ℃, 2.16k
g load).

When the ethylene content of the propylene-ethylene random copolymer is less than 1.0% by weight, the impact resistance of the resulting composition after γ-ray irradiation is lowered, while when it exceeds 6.0% by weight, transparency and high speed are obtained. Moldability decreases. The preferred ethylene content is 2.5 to 4.0% by weight. Further, if the melt flow rate of the propylene-ethylene random copolymer is less than 0.2 g / 10 min, sufficient transparency and moldability cannot be obtained, and if it exceeds 100 g / 10 min, the γ-ray irradiation results Impact resistance decreases. The preferred melt flow rate value is 9-80 g / 10 minutes. The propylene-ethylene random copolymer may be a mixture of two or more having the melt flow rate and the ethylene content, or the propylene-ethylene random copolymer may lose its properties. Homopolypropylene may be mixed to the extent that it does not exist.

In the present invention, it is also possible to use a propylene-ethylene random copolymer which is degraded in the presence of a radical generator so as to have a melt flow rate within the above range. The degradation may be carried out either before or after the (b) transparent nucleating agent and (c) silicone oil described below are compounded.

The molecular weight can be reduced by a conventional method, for example, by melt-kneading the above mixture in an extruder at 200 to 280 ° C. for 1 to 3 minutes in the presence of a radical generator such as a peroxide. Just go.

As the radical generator, it is preferable to use an organic peroxide. Specifically, methyl ethyl ketone peroxide, t-butylperoxyisopropyl carbonate, dicumyl peroxide, cumene hydroperoxide, 2,5-dimethyl-2,5-di (t-butylperoxide)
(Oxy) hexane, 2,5-dimethyl-2,5-di (t-butylperoxy) hexyne-3, di-t-butylperoxyphthalate and the like. These organic peroxides are used according to the desired melt flow rate, but usually 100 parts by weight of propylene-ethylene random copolymer,
It is used in a proportion of 0.01 to 0.1 parts by weight.

(B) Transparent Nucleating Agent In the present invention, the transparent nucleating agent is preferably a sorbitol compound or a phosphate compound.

Examples of the sorbitol compounds include dibenzylidene sorbitol, (1,3) 2,4-di (p-methylbenzylidene) sorbitol, (1,3) 2,4-di (p-chlorobenzylidene) sorbitol. , (1,3) 2,4-di (p-methoxybenzylidene) sorbitol and the like. Particularly, (1,3) 2,4-di (p-methylbenzylidene) sorbitol is preferable.

Examples of the phosphate compounds include 2-2'-methylenebis (4,6-di-t-butylphenyl) sodium phosphate and other phosphate compounds.

The amount of the transparent nucleating agent added is 0.10 to 0.8 part by weight based on 100 parts by weight of the above-mentioned (a) propylene-ethylene random copolymer. The amount of transparent nucleating agent added is 0.10.
If it is less than 10 parts by weight, the effect of improving transparency and high-speed moldability are not sufficient, and if it exceeds 0.8 parts by weight, it causes coloring on the contrary. The preferred amount of the transparent nucleating agent is 0.17 to 0.4
Parts by weight.

(C) Silicone Oil In the present invention, as the silicone oil, 1.42 to 1.
A material having a refractive index of 54 is used. If the refractive index of the silicone oil is less than 1.42, the transparency is lowered, while if it exceeds 1.54, the transparency is lowered. Thus, the reason why the transparency is changed by the refractive index is not always clear, but if the difference in the refractive index between the propylene-ethylene random copolymer and the silicone oil is smaller, the interlayer reflection is reduced and the transparency is increased. Conceivable. The preferred refractive index is 1.
48 to 1.51. Also, the viscosity of silicone oil is 5
It is preferably ˜5000 CS, especially 50 to 500 CS.

Silicone oils have each silicon atom bonded to at least one carbon atom and have a (-SiR ₁ R ₂
It is a polymer compound having -O-) as a repeating unit (however, Si comes to both ends of the repeating unit). The molecular weight of such silicone oil is generally 5 × 10 ² or more, and particularly preferably 1 × 10 ³ to 1 × 10 ⁵ .

The silicone oil has R ₁ and R ₂ of the silicone oil having the repeating unit as a methyl group, and a part of the methyl group is a phenyl group, α-methylstyrene, an alkyl group having 2 to 20 carbon atoms, etc. It is preferable that the structure is substituted with.

The silicone oil is added in an amount of 0.01 to 3.0 parts by weight per 100 parts by weight of (a) propylene-ethylene random copolymer. If the amount of silicone oil added is less than 0.01 parts by weight, the effect of improving the releasability due to the addition is not sufficient, while if it exceeds 3.0 parts by weight, not only the transparency decreases but also the screw penetrates into the screw during molding. Defects occur, the moldability is significantly deteriorated, and the molding becomes defective.
The preferred amount of silicone oil added is 0.05 to 0.1 part by weight.

(D) Other Ingredients The polypropylene composition of the present invention further comprises an antioxidant such as a hindered amine compound and a phosphorus compound, an inorganic filler such as talc, mica and titanium oxide, a neutralizing agent, and a heat stabilizer. Agents, antistatic agents and the like can be added as appropriate.

[2] Manufacturing Method The polypropylene composition of the present invention as described above is (a)
A propylene-ethylene random copolymer, (b) a transparent nucleating agent, (c) a silicone oil, and various additives which are optionally added are blended, and the mixture is added at 180 to 250 ° C, particularly 19
It can be obtained by melt-kneading at 0 to 230 ° C. As the kneading device, a non-open type Banbury mixer, a single-screw or twin-screw extruder, a kneader, a continuous mixer or the like can be used.

[0038]

In the present invention, the propylene-ethylene random copolymer is blended with a transparent nucleating agent and a silicone oil having a refractive index in a specific range, so that the resulting composition has excellent transparency. In addition, it exhibits excellent mold releasability, and is more effective in improving odor during molding as compared with the case of using a conventional amide-based mold release agent.

The reason why such an effect is obtained is not necessarily clear, but the addition amount of the transparent nucleating agent is added within a range that is optimum for the transparency of the composition, and a refractive index within a specific range is obtained. By compounding the silicone oil, the difference from the refractive index of the resin can be reduced and the interlayer reflection can be reduced, whereby the releasability can be improved without impairing the transparency obtained by the transparent nucleating agent. It is thought to be because of this.

[0040]

The present invention will be described in more detail by the following specific examples. In addition, in each of the Examples and Comparative Examples, the following additives were used. (1) Transparent nucleating agent N-1: (1,3) 2,4-di (p-methylbenzylidene) sorbitol [Gelol MD, manufactured by Shin Nippon Rika Co., Ltd.] N-2: phosphate compound [NA -21, manufactured by Asahi Denka Co., Ltd.] N-3: Phosphoric acid 2,2′-methylenebis (4,6-di-)
t-Butylphenyl) sodium [NA-11, manufactured by Asahi Denka Co., Ltd.] (2) Silicone oil Methylphenyl silicone oil S-1: [SH510, manufactured by Toray Dow Co., Ltd., viscosity 100 C
S, refractive index 1.425] S-2: [SH550, manufactured by Toray Dow Co., Ltd., viscosity 125 C
S, refractive index 1.496] S-3: [SH710, manufactured by Toray Dow Co., Ltd., viscosity 500 C
S, refractive index 1.533] S-4: [FZ197, manufactured by Nippon Unicar Co., Ltd., viscosity 40
0 CS, refractive index 1.505] α-methylstyrene-modified silicone oil S-5: [KF410, manufactured by Shin-Etsu Chemical Co., Ltd., viscosity 10
00CS, refractive index 1.480] Dimethyl silicone oil S-6: [SH200, manufactured by Toray Dow Co., Ltd., viscosity 100 C
S, refractive index 1.40] (3) Fatty acid amide OA: oleic acid amide SA: stearic acid amide

Examples 1 to 12 and Comparative Examples 1 to 11 Propylene-ethylene random copolymer (RPP: melt flow rate (230 ° C., 2.16 kg load) 15 g / 10 minutes, ethylene content 2.8% by weight) 100 parts by weight In contrast, the transparent nucleating agents (N-1 to N-3) in the amounts shown in Table 1, silicone oils (S-1 to S-6), and fatty acid amides (OA
Or SA: used only in Comparative Example) and premixed with a Henschel mixer. Next, this mixture was melt-kneaded and pelletized by an extruder (50 mmφ, single screw, L / D = 28) at 240 ° C. and 80 rpm.

Using the pellets thus obtained, a test piece for a physical property test described below was manufactured by Sumitomo Heavy Industries Ltd. 8
It was prepared by an ounce injection molding machine, and the transparency, the friction coefficient immediately after molding, the contact angle with silicone oil, and the odor were evaluated. The results are also shown in Table 1.

Table 1 Composition Example 1 Example 2 Example 3 Example 4 Example 5 RPP 100 100 100 100 100 Sorbitol compound N-1 0.2-0.2 0.2 0.2 N-2-0.3 --- Silicone oil S-1 0.03 0.07 - - - S-2 - - 0.05 0.1 - S-5 - - - - 0.07 was transparency ⁽¹⁾ 9.1 8.7 8.5 9.0 9.1 static friction coefficient ⁽²⁾ 0.52 0.45 0.49 0.40 0.58 contact angle ^{( 3)} 2.0 2.0 2.0 2.1 3.3 Odor ⁽⁴⁾ ○ ○ ○ ○ △

Table 1 (continued) Composition Example 6 Example 7 Example 8 Example 9 Example 10 RPP 100 100 100 100 100 100 Sorbitol-based compound N-1 0.4 0.4 --- N-2 ---- 0.2 0.2 N-3--0.3--Silicone oil S-1 ---- 0.01 S-2--0.07 3.0-S-3 0.07 ---- S-4-0.07 --- Physical property Transparency ^{(1 )} 8.5 8.3 9.1 9.5 8.8 Static friction coefficient ⁽²⁾ 0.47 0.47 0.39 0.19 0.58 Contact angle ⁽³⁾ 3.1 2.2 2.1 1.3 3.8 Odor ⁽⁴⁾ △ ○ ○ ○ ○

Table 1 (continued) Composition Example 11 Example 12 Comparative Example 1 Comparative Example 2 Comparative Example 3 RPP 100 100 100 100 100 Sorbitol compound N-1 0.13-0.2 0.3 0.2 N-2-0.8- − − Silicone oil S-2 0.10 0.10 − − − S-6 − − − 0.03 0.07 Physical properties Transparency ⁽¹⁾ 10.5 7.0 9.0 11.5 14.0 Static friction coefficient ⁽²⁾ 0.41 0.43 0.70 0.65 0.50 Contact angle ⁽³⁾ 2.0 2.1 5.0 4.0 4.0 Odor ⁽⁴⁾ ○ ○ ○ ○ ○

Table 1 (continued) Composition Comparative Example 4 Comparative Example 5 Comparative Example 6 Comparative Example 7 Comparative Example 8 RPP 100 100 100 100 100 100 Sorbitol compound N-1 0.3 0.4 0.2 0.4 0.2 Silicone oil S-2- - - - 4.0 fatty acid amide OA 0.05 0.05 - - - SA - - 0.07 0.10 - object transparency ⁽¹⁾ 9.5 12.0 14.0 16.0 - ^* static friction coefficient ⁽²⁾ 0.65 0.40 0.35 0.30 - ^* contact angle ⁽³⁾ 6.8 7.5 6.8 7.0 − ^* Odor ⁽⁴⁾ × × × × ○ Note) *: Poor molding.

[0047]

(1) Transparency: A 80 mm × 80 mm × 1 mm test piece (sheet) was prepared by injection molding, and the haze of the test piece was measured by a haze meter (manufactured by Suga Test Instruments Co., Ltd.). (2) Static friction coefficient immediately after molding: A sheet similar to the above (1) was slid on a hard aluminum plate immediately after molding, and the static friction coefficient was measured (pulling speed 50 mm / min, using strograph). (3) Contact angle: A predetermined amount of dimethyl silicone oil (100CS) was dropped on the surface of the sheet used in (1), and the contact angle at this time was measured by a goniometer-type contact angle meter (manufactured by Elma Co.). °). (4) Odor: 0.5 cm x sheet (comparative sample) similar to (1)
After chopping into 0.5 cm square pieces, 20 g of this fine piece was placed in a flask, and after leaving in a gear oven at 80 ° C. for 1 hour, the presence or absence of odor was checked for propylene-ethylene random copolymer 100.
A three-point comparison between two standard samples and one comparative sample, which were subjected to the same sheet molding and operation using the composition in which 0.2 part by weight of the sorbitol transparent nucleating agent (N-1) was added to the parts by weight. By the sensory test method by panel test (15 panels),
The following criteria evaluated. ◯: 12 or more out of 15 panelists judged that there was no difference in odor between the comparative sample and the standard sample, and the odor was slight or odorless. Δ: Less than 12 people judged that there was no difference in odor between the standard sample and the comparative sample, and less than 12 people judged that the comparative sample had a stronger odor than the standard sample. ×: 12 or more out of 15 panelists judged that the comparative sample had a stronger odor than the standard sample.

As is clear from Table 1, the polypropylene composition of the present invention is excellent in transparency, has a small coefficient of static friction immediately after molding (excellent releasability), and has a small contact angle with silicone oil. Moreover, it had almost no odor. On the other hand, the composition of each comparative example was significantly inferior in at least one of these physical properties.

[0050]

As described in detail above, in the present invention, a propylene-ethylene random copolymer, a transparent nucleating agent, and
Since the composition obtained is blended with a silicone oil having a refractive index in a specific range, the composition obtained is excellent in transparency and, when formed into a molded article such as a tubular article, when the silicone oil is applied to the inner surface, It has good wettability with silicone oil and exhibits good mold releasability.

The polypropylene composition of the present invention as described above is suitable for medical instruments, stationery, miscellaneous goods, food packaging materials, etc., especially for microsyringes.

Claims (1)

[Claims] 1. An ethylene content of 1.0 to 6.0% by weight and a melt flow rate of 0.2 to 100 g / 10 min (230).
C., 2.16 kg load) 100 parts by weight of propylene-ethylene random copolymer, (b) 0.10 to 0.8 parts by weight of transparent nucleating agent, and (c) 0.01 to 3.0 parts by weight of silicone oil having a refractive index of 1.42 to 1.54. And a polypropylene composition.